LRRC10 is required to maintain cardiac function in response to pressure overload

Abstract

Brody MJ, Feng L, Grimes AC, Hacker TA, Olson TM, Kamp TJ, Balijepalli RC, Lee Y. LRRC10 is required to maintain cardiac function in response to pressure overload. Am J Physiol Heart Circ Physiol 310: H269 -H278, 2016. First published November 25, 2015 doi:10.1152/ajpheart.00717.2014.-We previously reported that the cardiomyocyte-specific leucine-rich repeat containing protein (LRRC)10 has critical functions in the mammalian heart. In the present study, we tested the role of LRRC10 in the response of the heart to biomechanical stress by performing transverse aortic constriction on Lrrc10-null (Lrrc10 Ϫ/Ϫ ) mice. Mild pressure overload induced severe cardiac dysfunction and ventricular dilation in Lrrc10 Ϫ/Ϫ mice compared with control mice. In addition to dilation and cardiomyopathy, Lrrc10 Ϫ/Ϫ mice showed a pronounced increase in heart weight with pressure overload stimulation and a more dramatic loss of cardiac ventricular performance, collectively suggesting that the absence of LRRC10 renders the heart more disease prone with greater hypertrophy and structural remodeling, although rates of cardiac fibrosis and myocyte dropout were not different from control mice. Lrrc10 Ϫ/Ϫ cardiomyocytes also exhibited reduced contractility in response to ␤-adrenergic stimulation, consistent with loss of cardiac ventricular performance after pressure overload. We have previously shown that LRRC10 interacts with actin in the heart. Here, we show that His 150 of LRRC10 was required for an interaction with actin, and this interaction was reduced after pressure overload, suggesting an integral role for LRRC10 in the response of the heart to mechanical stress. Importantly, these experiments demonstrated that LRRC10 is required to maintain cardiac performance in response to pressure overload and suggest that dysregulated expression or mutation of LRRC10 may greatly sensitize human patients to more severe cardiac disease in conditions such as chronic hypertension or aortic stenosis. CARDIOMYOCYTE HYPERTROPHY in response to extracellular stimuli, such as neurohumoral or growth factor stimulation of membrane-bound receptors (13, 23, 44), or in response to mechanical stretch or strain that is sensed by mechanosensory machinery embedded in the Z-disc cytoskeleton, and sarcolemma (25, 38, 49). At the whole organ level, the heart undergoes hypertrophy as an adaptive mechanism to maintain cardiac output and reduce ventricular wall stress (20,23,38). While initially beneficial, prolonged cardiac hypertrophy becomes maladaptive and progresses to cardiac dilation, decompensation, heart failure, and/or sudden death (20,23,38). Cardiac hypertrophy can be induced by a number of cardiovascular diseases, such as myocardial infarction or chronic hypertension (23, 37). Indeed, high blood pressure is a common precursor to heart disease, particularly in the United States, where chronic hypertension is widespread (18,21,42). Despite increased awareness and treatment of hypertension, recent epidemiological studies have suggested that its prevalence con...

Molecular pathological study on LRRC10 in sudden unexplained nocturnal death syndrome in the Chinese Han population

“…Most recently, the identification of rare variants of LRRC10 in unrelated idiopathic DCM patients confirmed LRRC10 as a novel DCM-susceptibility gene [10]. LRRC10 is also needed to maintain cardiac function in response to pressure overload [29]. Taken together, LRRC10 is necessary for normal cardiac development and function.…”

Defective Flux of Thrombospondin-4 through the Secretory Pathway Impairs Cardiomyocyte Membrane Stability and Causes Cardiomyopathy

“…mdx mice were on the C57/BL10 genetic background, Thbs4 Ϫ/Ϫ mice were on the C57BL/6-SV129 background, and all transgenic mice were on the FVB/N background. Echocardiography was performed on anesthetized adult mice to noninvasively evaluate cardiac structure and function as described previously (50,51). Transverse aortic constriction (TAC) to induce cardiac pressure overload was performed as described previously (50).…”

“…Echocardiography was performed on anesthetized adult mice to noninvasively evaluate cardiac structure and function as described previously (50,51). Transverse aortic constriction (TAC) to induce cardiac pressure overload was performed as described previously (50). All procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals (52) and approved by the Institutional Animal Care and Use Committee (IACUC) of Cincinnati Children's Hospital Medical Center.…”

“…For seminative PAGE, cardiomyocyte lysates were harvested in Tris-buffered saline (TBS) with 1% n-dodecyl ␤-D-maltoside (DDM) with protease inhibitors (Roche), cleared by centrifugation, and prepared for SDS-PAGE by addition of 2ϫ native PAGE sample buffer (62.5 mM Tris-HCl [pH 6.8], 40% glycerol, 0.01% bromophenol blue) without boiling. For immunoblotting of mouse cardiac or Drosophila proteins, mouse hearts or whole flies were homogenized in RIPA buffer (50 mM Tris-HCl [pH 7.4], 1% Triton X-100, 1% sodium deoxycholate, 1 mM EDTA, 0.1% SDS), sonicated, and cleared by centrifugation as described previously (50,51).…”

“…Immunohistochemistry, histology, and electron microscopy. Immunostaining experiments were performed as previously described (50,51,55). Briefly, paraformaldehyde-fixed paraffin-embedded cardiac sections were incubated in blocking solution (PBS, 5% goat serum, 1% bovine serum albumin [BSA], 1% glycine, 0.2% Triton X-100) for 1 h and then with anti-Thbs4 primary antibody (Santa Cruz) diluted 1:500 in blocking solution overnight, followed by incubation with Alexa Fluor-labeled secondary antibody (Invitrogen; 1:1,000) for 1 h. For immunocytochemistry, adult mouse cardiomyocytes were isolated from mouse hearts by Langendorff perfusion, fixed in 4% paraformaldehyde, and immunostained in suspension as described previously (51) using antibodies against ␤sarcoglycan (Novus Biologicals) and GM130 (BD Biosciences) coupled to Alexa Fluor-labeled secondary antibodies (Invitrogen).…”